A State Rarity Rank of S2S3 means: Imperiled or Vulnerable in New York - Very vulnerable to disappearing from New York, or vulnerable to becoming imperiled in New York, due to rarity or other factors; typically 6 to 80 populations or locations in New York, few individuals, restricted range, few remaining acres (or miles of stream), and/or recent and widespread declines. More information is needed to assign a single conservation status.

Global Rarity Rank:G4

A Global Rarity Rank of G4 means: Apparently secure globally, though it may be quite rare in parts of its range, especially at the periphery.

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Because of its relatively thin shell, this species has suffered greatly from the zebra mussel (Dreissena polymorpha) invasion (Strayer and Jirka 1997).

This species has been heavily impacted by the zebra mussel invasion in the St. Lawrence River basin, Hudson River estuary, lower Great Lakes and elsewhere throughout the state (Strayer and Jirka 1997).

Although not widespread in the state, L. nasuta can still be encountered regularly, and is sometimes abundant (Strayer and Jirka 1997). Average densities in the tidal Hudson River prior to the zebra mussel invasion were 0.08/sq. meter (Strayer et al. 1994), but densities were not reported post invasion. Only 3 individuals of this species were found in a late 1980's survey of 52 sites in many watersheds in the Lake Erie and Ontario basins (Strayer et al. 1991).

This species was once a major component of the lower Great lakes drainage basin, but is now virtually absent owing to the zebra mussel invasion. Ligumia nasuta comprised about 5% of the pre-1960 Unionid records in the lower Great Lakes in Ontario, but dropped to 2.5% of the records post-1960. Between 1930 to 1982 this species was the second most common Unionid in western Lake Erie (Nalepa et al. 1991), but by 1991 it had disappeared (Schloesser and Nalepa 1994). All of the records of live animals from the St. Lawrence drainage basin in New York are pre-1970.